"To investigate how the metabolic cost of the brain scales with
brain size and whether the metabolic cost per neuron increases
with neuronal size, it is necessary to examine how total energy
consumption relates to the number of neurons in different brains.
This analysis was made possible only recently, by the determination of numbers of neurons in the whole brain and its main
structures [24–28]."

Comments

"Consistently with the linear variation in total glucose use
depending on the number of neurons in the structure, the estimated
average glucose use per neuron within each structure is remarkably
constant across species (Table 1), as is the average oxygen use per
neuron for the whole brain (Table 2), considering that the small 0.4-fold variations in average glucose use per neuron occur across a
1,000-fold variation in numbers of neurons and total glucose use
and a 3-fold variation in neuronal density for the whole brain."